Shaker Aamer has admitted he travelled on a false passport as it was the only way he could leave the country.
Him and his wife and children later travelled to Taliban-led Afghanistan using the document.
He said Afghanistan was where they felt "comfortable" as his wife had suffered abuse in the UK because she wore traditional Muslim dress.
With his wide, familiar smile, Shaker Aamer has become the image of resilience, writes Julie Etchingham - but now, he's a man on a mission.
The last Brit to be released from Guantanamo told ITV News he broke down in tears when he first met his children at their emotional reunion.
A Saudi national and British resident, detained at Guantanamo for 14 years without charge - here's what you need to know about Shaker Aamer.